#include "my_stdio.h"
#include "string.h"
#include "stdlib.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

mFILE* myopen(const char* filename, const char* mode)
{
    int fd = -1;
    if(strcmp(mode,"r") == 0)
    {
        fd = open(filename,O_RDONLY);
    }
    else if(strcmp(mode,"w") == 0)
    {
        fd = open(filename,O_CREAT | O_WRONLY | O_TRUNC,0666);
    }
    else if(strcmp(mode,"a") == 0)
    {
        fd = open(filename,O_CREAT | O_WRONLY | O_APPEND,0666);
    }
    if(fd < 0) return NULL;
    mFILE* mf = (mFILE*)malloc(sizeof(mFILE));
    if(!mf)
    {
        close(fd);
        return NULL;
    }
    mf->flag = FLUSH_LINE;
    mf->fileno = fd;
    mf->cap = SIZE;
    mf->size = 0;

    return mf;

}

void myfflush(mFILE* stream)
{
    //写到内核文件缓冲区
    write(stream->fileno,stream->outbuffer,stream->size);

    stream->size = 0;
}

int mywrite(const void* ptr,int num,mFILE* stream)
{
    //拷贝
    memcpy(stream->outbuffer+stream->size,ptr,num);
    stream->size += num;
    //刷新缓冲区
   if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1] == '\n')
   {
       myfflush(stream);
   }
   return num;
}

void myclose(mFILE* stream)
{
    if(stream->size > 0)
    {
        myfflush(stream);
    }
    close(stream->fileno);
}
